I enjoyed the discussions of fractals and complexity theory. My biggest major takeaways were all related to the scaling effects of life and biology and self-similarity around different species. The company stuff was also interesting, but less compelling from my standpoint (or maybe I've just read more in that department before), and the area I found least interesting was the city stuff, but it was still well written and had good information.

I definitely recommend this to anyone interested in biology and science/math in general. Below are my main notes and takeaways from the book.

1 the big picture8M life formsComplexityCommonalities between life and companies and cities Number of heartbeats same across life formsMagic number 4Global urbanization. Exponential expansionWhy cities remain while individuals and companies dieEnergy key to metabolism for multiple purposes. Entropy kills. Size matters. Nonlinear scaling. Scaling and complexity. Emergence. Self-organization. Resilience. Adaptive dynamics. Where whole is different and more complex than just combo of cells. You are your networks. Power law. Power of 4 in exponent. Cities scale predictably

2 the measure of all thingsGalileoFundamental constraints of scaling up organic things. Areas and volumes scaling. Collapsing under its own weight. Volumes increase much faster than areas. Strength and dissipating heat based on cross-sectional area. There are limits to scaling size and weight. Relative strength increases as size decreases. Orders of magnitude, logs, Richter scale. Drug dosages not scaling linearly. Scale with surface area not volume/weight. Scale by ⅔ exponent not linearly. Problems with classic BMI. Innovation and limits to growth. Innovation can change character and material and allow bypassing limits. Brunel. Engineer. Froude and modeling theory. Problems when scaling up physical designs of ships and railroads. Turbulence. Similarity and similitude. Dimensionless quantities like ratios. Pure numbers.

4 the fourth dimension of lifeFractality gives extra fourth dimension. Fractal cross section and length measurements for fractal networks in bodies like respiratory network. Man-made things don’t have fractal dimensions. Cities and companies do. Why no mammals smaller than ants? Why hi mammals the size of Godzilla? Interface between capillaries and cells. GrowthWe stop growing because maintenance of cells starts to match energy for creating them once we are big enough. ¾ exponent scaling metabolic rate. Universal growth equation across animalsglobal warming and exponential scaling of temperatureEverything about growth and death tied to average energy to activate an ATP moleculeSmall temperature change increases metabolic stress much fasterAging and mortality. Maximum human lifespan around 120. 1.5 billion heartbeats per life for all mammals. Caloric restriction lowers metabolic rate and increases lifespan

5 anthropocene to urbanoceneExponentially expanding universeCities and global sustainability. Exponential growth. Constant or shortening doubling time. Quick demise in final generations of growth or descent. Rise of industrial city and discontents. Malthus and great innovation optimistsIt’s all energy.

6 A prelude to a science of citiesAre cities large organisms

7 toward a science of citiesGiven city size alone, can predict accurately number of patents and disease and other metricsCities or fractalsSocial and intellectual connections

8 consequences and predictionsCities speed up timeOne hour rule: almost everyone travels to/from work 1 hour per day (no matter what method of transportation, so city size increases). Marketti’s constant. Increasing pace of walking with city sizeInverse square law for visitors to a site based on distance

9 toward a science of companiesScaling rules apply to companies by power law. They’re self similar even across industries. Zip’s law. Myth of open ended growth. Companies will eventually die.Companies die but cities don’t. Cities more decentralized and bottom up. Companies more centralized and top down.